Conferences, Draft Picks, and Total Draft Value
I have recently been working with a geo-coded college football recruiting data set which was graciously provided to me by Aaron Mulhollen, a Doctoral candidate in geography at George Mason University. Aaron sourced the data from the 24/7 Sports composite recruiting database, scrubbed it, and added the geo-coding data. Currently I am putting the finishing touches on the addition of detailed NFL draft data to the data set. Once complete, the data set will allow all sorts of analysis that I am very excited about. In the meantime, one by-product of the work that I have been doing is that I have a detailed set of NFL draft data, which is interesting in its own right. So I thought I would throw together a quick post on it.
The Big Picture: The NFL Draft is All About Power 5 Players
The key thing that I did with the raw draft data set that is available everywhere is that I added level/division data to every college program that produced an NFL draft pick over the past decade, including conferences for the FBS programs. This allows a presentation that I have never seen before:
I knew that the majority of players drafted into the NFL come out of Power 5 football programs, but I never would have guessed the degree to which Power 5 schools dominate the draft. NFL teams spend 73% of their draft picks on players from the Power 5 conferences compared to just 18% from the Group of 5. The remainder is primarily made up of FCS players (7%), with Division II players have accounting for another 2%. All other sources (D-III, Canada, etc.) make up the remaining 1%.
Even this analysis understates the dominance of the Power 5 schools in the draft, however. Since earlier picks have more value than later picks, the draft capital that NFL teams spend on Power 5 players is significantly higher than even the raw number of picks indicates.
There are a number of ways to estimate the relative value of picks throughout the draft, but for simplicity I have used the "classic" draft position trade value chart that was originally credited to Jimmy Johnson. The table below presents that draft value data on a percentage basis.
Based on the Jimmy Johnson formulation, NFL teams spend almost 86% of their draft capital on players from Power 5 schools versus about 12% from G5 players. And next to nothing on players from anywhere else.
Now, I suspect that Johnson's formula may undervalue picks later in the draft. And I further suspect that NFL teams may spend too little draft capital on prospects from the Group of 5. But both of those analyses will have to wait for another day.
Among Conferences in the Draft, the SEC is King
Slicing the players drafted out of FBS schools by conference (all figures are based on current conference configurations) and round underscores one of the least surprising conclusions possible: the NFL loves players from the SEC. An interesting observation is that while the Power 5 conferences have fairly even distribution of picks across rounds, and the SEC does in Rounds 2 - 7, there is a big ol' outlier in Round 1 for the SEC. Whether this is due to bias or actual value is another question that I can't answer today.
The fact the ACC, Big Ten and Pac 12 are all grouped relatively close together is also interesting. In fact, adjusting for difference in conference sizes, the numbers are stunningly close: 25.7 picks per member for the ACC, 26.7 picks per member for the Big Ten, and 27.8 picks per member for the Pac-12.
The Big XII lags substantially behind the other Power 5 conferences both in terms of absolute number and also on a per member basis.
Extending this analysis from raw picks to total pick value (see chart below) further cements the SEC's status. It also highlights how close the ACC and Pac 12 are, mainly due to the unusually large number of early second round picks for the Pac 12.
Another interesting way to view the draft value data is over time. The bubble chart below shows the total pick value by conference by year. This illustrates that while the SEC is dominant overall, it isn't necessarily far and away the top conference every year. In fact, in 2015 it was number 3 overall in terms of aggregate pick value, although the Pac-12, ACC, and SEC were all very tightly grouped that year.
Adjusting for Membership, the Pac-12 is Clearly Next in Line
While the Pac-12 has had a rough decade or so since Pete Carroll's golden era at USC, it's clear that the conference is still a major producer of talent for the NFL. On a per member basis the Pac-12 is second both in raw picks and in aggregate draft value (see table below).
I'll follow this post up with some interesting slices of draft picks and draft value by college program (spoiler: Alabama is going to do very well) in the near future.
In the meantime, follow follow CFB Data Lab on Twitter for quick bits of analysis and previews of things I am working on.